Question 815293
"1 and 2 combined" translates into "add runner 1's and runner 2's distances:
{{{4/x+5x}}}
To add we must have the same denominator:
{{{4/x+(5x/1)(x/x)}}}
{{{4/x+5x^2/x)}}}
{{{(4+5x^2)/x)}}}<br>
"much more did runner 3 run than runner 1 and 2 combined" translates into "subtract runner 3's distance minus ... runner 1 and 2 combined":
{{{(2x+2)/x^2-(4+5x^2)/x)}}}
Again we need the same denominator to subtract:
{{{(2x+2)/x^2-((4+5x^2)/x)(x/x)}}}
{{{(2x+2)/x^2-(4x+5x^3)/x^2}}}
Subtracting:
{{{(-2x+2-5x^3)/x^2}}}